About all that one can do is to guess. I tend to suspect that the first response is right about the one marked "hot water tank." The Arctic could be also, or just about anything else for cold weather. I would check under the rig and look at the tanks to see if there are heat pads there. If so, turn on the Arctic switch and after an hour or two, if it is cool outside you should be able to detect the warming effect.
I assume that these switches are located on some sort of control panel or display panel?
Firan is on longer in existence so your best bet is some owner.